在 Linux 上為 Aarch64（yocto）交叉編譯 OpenCV 無法構建

Question

我檢查了 opencv 源並能夠在 linux 上為 x86_64 構建，但未能在 Linux 上為 Aarch 進行交叉編譯。

對於 Linux 我使用了以下命令，它工作得很好：

  5 #inside build folder
  6 
  7 cmake -D CMAKE_BUILD_TYPE=RELEASE \
  8 -D CMAKE_INSTALL_PREFIX=/usr/local \
  9 -D OPENCV_EXTRA_MODULES_PATH=/usr/local/opencv_contrib/modules \
 10 -D OpenBLAS_INCLUDE_DIR=/usr/include/x86_64-linux-gnu \
 11 -D OpenBLAS_LIB=/usr/lib/x86_64-linux-gnu/libopenblas.so \
 12 -D INSTALL_TESTS=ON \
 13 -D INSTALL_C_EXAMPLES=ON \
 14 -D WITH_PYTHON=ON \
 15 -D INSTALL_PYTHON_EXAMPLES=ON ..
 16 
 17 
 18 make -j4

同樣，我使用以下命令進行交叉編譯：

  6 #inside build folder
  7 
  8 cmake -D CMAKE_BUILD_TYPE=RELEASE \
  9 -D CMAKE_TOOLCHAIN_FILE=/usr/local/opencv/platforms/linux/aarch64-gnu.toolchain.cmake \
 10 -D INSTALL_TESTS=ON \
 11 -D INSTALL_C_EXAMPLES=ON \
 12 -D WITH_PYTHON=ON \
 13 -D SOFTFP=ON \
 14 -D INSTALL_PYTHON_EXAMPLES=ON ..
 15 
 16 
 17 make -j4
 18 

~

它在 cmake 命令中失敗。 它說“配置不完整，發生錯誤！”

output如下：

-- Detected processor: aarch64
-- Looking for ccache - not found
-- NEON is not supported by C++ compiler
-- FP16 is not supported by C++ compiler
-- Optimization NEON is not available, skipped
-- Optimization FP16 is not available, skipped
-- OpenCV disables pkg-config to avoid using of host libraries. Consider using PKG_CONFIG_LIBDIR to specify target SYSROOT
-- Could NOT find ZLIB (missing: ZLIB_LIBRARY ZLIB_INCLUDE_DIR) (Required is at least version "1.2.3")
-- Could NOT find JPEG (missing: JPEG_LIBRARY JPEG_INCLUDE_DIR) 
-- libjpeg-turbo: VERSION = 2.0.6, BUILD = opencv-4.5.1-dev-libjpeg-turbo
-- Could NOT find TIFF (missing: TIFF_LIBRARY TIFF_INCLUDE_DIR) 
-- Could NOT find OpenJPEG (minimal suitable version: 2.0, recommended version >= 2.3.1). OpenJPEG will be built from sources
-- OpenJPEG: VERSION = 2.3.1, BUILD = opencv-4.5.1-dev-openjp2-2.3.1
-- OpenJPEG libraries will be built from sources: libopenjp2 (version "2.3.1")
-- Could NOT find PNG (missing: PNG_LIBRARY PNG_PNG_INCLUDE_DIR) 
-- Could not find OpenBLAS include. Turning OpenBLAS_FOUND off
-- Could not find OpenBLAS lib. Turning OpenBLAS_FOUND off
-- Could NOT find Atlas (missing: Atlas_CBLAS_INCLUDE_DIR Atlas_CLAPACK_INCLUDE_DIR Atlas_CBLAS_LIBRARY Atlas_BLAS_LIBRARY Atlas_LAPACK_LIBRARY) 
-- Could NOT find BLAS (missing: BLAS_LIBRARIES) 
-- LAPACK requires BLAS
-- A library with LAPACK API not found. Please specify library location.
-- Carotene: NEON is not available, disabling carotene...
-- OpenCV Python: during development append to PYTHONPATH: /usr/local/opencv/build/python_loader
-- Allocator metrics storage type: 'int'
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.sse2.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.sse3.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.ssse3.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.sse4_1.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.sse4_2.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.avx.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.fp16.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.avx2.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin128.avx512_skx.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin256.avx2.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin256.avx512_skx.cpp
-- Excluding from source files list: <BUILD>/modules/core/test/test_intrin512.avx512_skx.cpp
-- Excluding from source files list: modules/imgproc/src/corner.avx.cpp
-- Excluding from source files list: modules/imgproc/src/imgwarp.avx2.cpp
-- Excluding from source files list: modules/imgproc/src/imgwarp.sse4_1.cpp
-- Excluding from source files list: modules/imgproc/src/resize.avx2.cpp
-- Excluding from source files list: modules/imgproc/src/resize.sse4_1.cpp
-- Registering hook 'INIT_MODULE_SOURCES_opencv_dnn': /usr/local/opencv/modules/dnn/cmake/hooks/INIT_MODULE_SOURCES_opencv_dnn.cmake
-- opencv_dnn: filter out cuda4dnn source code
-- Excluding from source files list: <BUILD>/modules/dnn/layers/layers_common.avx.cpp
-- Excluding from source files list: <BUILD>/modules/dnn/layers/layers_common.avx2.cpp
-- Excluding from source files list: <BUILD>/modules/dnn/layers/layers_common.avx512_skx.cpp
-- Excluding from source files list: modules/features2d/src/fast.avx2.cpp
-- 
-- General configuration for OpenCV 4.5.1-dev =====================================
--   Version control:               4.5.1-64-gd34a34f328
-- 
--   Platform:
--     Timestamp:                   2021-01-13T11:12:36Z
--     Host:                        Linux 5.4.0-58-generic x86_64
--     Target:                      Linux 1 aarch64
--     CMake:                       3.16.3
--     CMake generator:             Unix Makefiles
--     CMake build tool:            /usr/bin/make
--     Configuration:               RELEASE
-- 
--   CPU/HW features:
--     Baseline:
--       requested:                 NEON FP16
--       required:                  NEON
--       disabled:                  VFPV3
-- 
--   C/C++:
--     Built as dynamic libs?:      YES
--     C++ standard:                11
--     C++ Compiler:                /usr/bin/c++  (ver 9.3.0)
--     C++ flags (Release):         -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG  -DNDEBUG
--     C++ flags (Debug):           -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -fvisibility=hidden -fvisibility-inlines-hidden -g  -O0 -DDEBUG -D_DEBUG
--     C Compiler:                  /usr/bin/cc
--     C flags (Release):           -fsigned-char -W -Wall -Werror=return-type -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -fvisibility=hidden -O3 -DNDEBUG  -DNDEBUG
--     C flags (Debug):             -fsigned-char -W -Wall -Werror=return-type -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -fvisibility=hidden -g  -O0 -DDEBUG -D_DEBUG
--     Linker flags (Release):      -Wl,--gc-sections -Wl,--as-needed  
--     Linker flags (Debug):        -Wl,--gc-sections -Wl,--as-needed  
--     ccache:                      NO
--     Precompiled headers:         NO
--     Extra dependencies:          dl m pthread rt
--     3rdparty dependencies:
-- 
--   OpenCV modules:
--     To be built:                 calib3d core dnn features2d flann gapi highgui imgcodecs imgproc ml objdetect photo stitching ts video videoio
--     Disabled:                    world
--     Disabled by dependency:      -
--     Unavailable:                 java python2 python3
--     Applications:                tests perf_tests apps
--     Documentation:               NO
--     Non-free algorithms:         NO
-- 
--   GUI: 
--     GTK+:                        NO
-- 
--   Media I/O: 
--     ZLib:                        zlib (ver 1.2.11)
--     JPEG:                        libjpeg-turbo (ver 2.0.6-62)
--     WEBP:                        build (ver encoder: 0x020f)
--     PNG:                         build (ver 1.6.37)
--     TIFF:                        build (ver 42 - 4.0.10)
--     JPEG 2000:                   build (ver 2.3.1)
--     HDR:                         YES
--     SUNRASTER:                   YES
--     PXM:                         YES
--     PFM:                         YES
-- 
--   Video I/O:
--     DC1394:                      NO
--     FFMPEG:                      NO
--       avcodec:                   NO
--       avformat:                  NO
--       avutil:                    NO
--       swscale:                   NO
--       avresample:                NO
--     GStreamer:                   NO
--     v4l/v4l2:                    YES (linux/videodev2.h)
-- 
--   Parallel framework:            pthreads
-- 
--   Trace:                         YES (with Intel ITT)
-- 
--   Other third-party libraries:
--     Lapack:                      NO
--     Custom HAL:                  NO
--     Protobuf:                    build (3.5.1)
-- 
--   OpenCL:                        YES (no extra features)
--     Include path:                /usr/local/opencv/3rdparty/include/opencl/1.2
--     Link libraries:              Dynamic load
-- 
--   Python (for build):            /usr/bin/python2.7
-- 
--   Install to:                    /usr/local/opencv/build/install
-- -----------------------------------------------------------------
-- 
-- Configuring incomplete, errors occurred!
See also "/usr/local/opencv/build/CMakeFiles/CMakeOutput.log".
See also "/usr/local/opencv/build/CMakeFiles/CMakeError.log".

Answer 1

正如 cmake output 告訴您的那樣，找不到各種庫 - 請參閱各種Could NOT find xxx消息。

您必須確保安裝了這些庫的aarch64版本（並且 cmake 可以找到它們）。 是否有可用於aarch64架構的預構建包取決於您的系統/包管理器。 檢查現有包 - 否則您必須自己構建（和安裝）這些庫（再次：對於aarch64架構）。